Prior to 2012/04, the Emacs repository used to contain many more tags.
Apparently these date from ye olden days, when tags were common
to several GNU projects.  So many of them had no relevance to Emacs,
and hence were removed.  See:

http://lists.gnu.org/archive/html/emacs-devel/2012-04/msg00042.html

(UPDATE: It seems tag deletion is basically impossible in bzr, so all
these tags came back.)

In the unlikely event that you need them, the removed tags were:

tag                       revision

amigados-merge            14846
before-thomas-posix1996   16843
gcc-2_8_1-980401          20893
gcc-2_8_1-980402          21795
gcc-2_8_1-980407          20893
gcc-2_8_1-980412          20893
gcc-2_8_1-980413          20893
gcc-2_8_1-980419          21502
gcc-2_8_1-980426          21502
gcc-2_8_1-980502          21795
gcc-2_8_1-980513          21795
gcc-2_8_1-980525          22147
gcc-2_8_1-980529          22147
gcc-2_8_1-980608          22147
gcc-2_8_1-980609          22147
gcc-2_8_1-980627          22478
gcc-2_8_1-980705          22478
gcc-2_8_1-980718          22478
gcc-2_8_1-980811          22971
gcc-2_8_1-980813          23005
gcc-2_8_1-980928          23338
gcc-2_8_1-980929          23338
gcc-2_8_1-RELEASE         20893
gcc_2_8_1-980315          20893
gcc_2_8_1-980929          23338
glibc-2_0_2               16843
gnumach-release-1-1       17693
gnumach-release-1-1-1     17693
gnumach-release-1-1-2     18209
gnumach-release-1-1-3     18209
hurd-release-0-2          18209
jimb-sync-Nov-3-1992       1552
libc20x-97031             16843
libc20x-970306            16843
libc20x-970316            16843
libc20x-970318            16843
libc20x-970319            16843
libc20x-970404            16843
libc-1-90                 15360
libc-1-91                 15451
libc-1-92                 15463
libc-1-93                 15702
libc-950402               11085
libc-950411               11255
libc-950722               12418
libc-950723               12418
libc-950922               12859
libc-951016               12859
libc-951018               13231
libc-951029               13231
libc-951031               13231
libc-951101               13231
libc-951102               13231
libc-951103               13231
libc-951104               13231
libc-951105               13231
libc-951106               13231
libc-951107               13231
libc-951108               13231
libc-951109               13231
libc-951110               13231
libc-951111               13231
libc-951112               13231
libc-951113               13231
libc-951114               13231
libc-951115               13231
libc-951116               13231
libc-951117               13231
libc-951118               13231
libc-951119               13231
libc-951120               13231
libc-951121               13231
libc-951122               13231
libc-951123               13231
libc-951124               13231
libc-951125               13231
libc-951126               13231
libc-951127               13231
libc-951128               13231
libc-951129               13231
libc-951130               13231
libc-951201               13679
libc-951202               13679
libc-951203               13679
libc-951204               13679
libc-951206               13686
libc-951208               13693
libc-951209               13693
libc-951210               13693
libc-951211               13693
libc-951212               13704
libc-951213               13704
libc-951214               13730
libc-951215               13730
libc-951216               13741
libc-951217               13741
libc-951218               13741
libc-951219               13741
libc-951220               13741
libc-951221               13741
libc-951222               13741
libc-951223               13741
libc-951224               13741
libc-951225               13741
libc-951226               13741
libc-951227               13741
libc-951228               13741
libc-951229               13741
libc-951230               13741
libc-951231               13741
libc-960101               13741
libc-960102               13741
libc-960103               13741
libc-960104               13741
libc-960105               13741
libc-960106               13741
libc-960107               13741
libc-960108               13741
libc-960109               13741
libc-960110               13741
libc-960111               13741
libc-960112               13741
libc-960113               13741
libc-960114               13741
libc-960115               13741
libc-960116               14192
libc-960117               14192
libc-960118               14213
libc-960119               14213
libc-960120               14213
libc-960121               14213
libc-960122               14213
libc-960123               14213
libc-960124               14213
libc-960125               14213
libc-960126               14213
libc-960127               14213
libc-960128               14213
libc-960129               14213
libc-960130               14213
libc-960131               14213
libc-960201               14449
libc-960202               14449
libc-960203               14473
libc-960204               14473
libc-960205               14473
libc-960206               14473
libc-960207               14473
libc-960208               14473
libc-960209               14473
libc-960210               14473
libc-960211               14540
libc-960212               14548
libc-960213               14562
libc-960214               14562
libc-960215               14562
libc-960216               14562
libc-960217               14562
libc-960218               14562
libc-960219               14562
libc-960220               14562
libc-960221               14562
libc-960222               14562
libc-960223               14562
libc-960224               14562
libc-960225               14562
libc-960226               14562
libc-960227               14562
libc-960228               14562
libc-960229               14562
libc-960302               14724
libc-960303               14724
libc-960304               14724
libc-960305               14753
libc-960306               14764
libc-960307               14764
libc-960308               14764
libc-960309               14764
libc-960310               14764
libc-960311               14764
libc-960312               14764
libc-960313               14764
libc-960314               14764
libc-960315               14809
libc-960316               14809
libc-960317               14809
libc-960318               14809
libc-960319               14809
libc-960320               14809
libc-960321               14809
libc-960322               14855
libc-960323               14855
libc-960324               14855
libc-960325               14855
libc-960326               14855
libc-960327               14855
libc-960328               14855
libc-960329               14912
libc-960330               14912
libc-960331               14912
libc-960401               14912
libc-960402               14912
libc-960403               14912
libc-960404               14912
libc-960405               14912
libc-960406               14912
libc-960407               14912
libc-960408               14912
libc-960409               14962
libc-960410               14962
libc-960411               14962
libc-960412               14962
libc-960413               15014
libc-960414               15014
libc-960415               15014
libc-960416               15014
libc-960417               15014
libc-960418               15014
libc-960419               15014
libc-960420               15014
libc-960421               15014
libc-960422               15014
libc-960423               15014
libc-960424               15014
libc-960425               15014
libc-960426               15014
libc-960427               15014
libc-960428               15014
libc-960429               15014
libc-960430               15014
libc-960501               15014
libc-960502               15014
libc-960503               15014
libc-960504               15014
libc-960505               15014
libc-960506               15014
libc-960507               15014
libc-960508               15014
libc-960509               15014
libc-960510               15014
libc-960511               15014
libc-960512               15014
libc-960513               15014
libc-960514               15014
libc-960515               15014
libc-960516               15014
libc-960517               15014
libc-960518               15014
libc-960519               15014
libc-960520               15014
libc-960521               15261
libc-960522               15278
libc-960523               15278
libc-960524               15278
libc-960525               15287
libc-960526               15287
libc-960527               15287
libc-960528               15287
libc-960529               15287
libc-960530               15287
libc-960531               15287
libc-960601               15287
libc-960602               15287
libc-960603               15287
libc-960604               15319
libc-960605               15334
libc-960606               15334
libc-960607               15334
libc-960608               15360
libc-960609               15360
libc-960610               15360
libc-960611               15360
libc-960612               15360
libc-960613               15360
libc-960614               15360
libc-960615               15360
libc-960616               15360
libc-960617               15360
libc-960618               15360
libc-960619               15451
libc-960620               15451
libc-960621               15463
libc-960622               15463
libc-960623               15463
libc-960624               15463
libc-960625               15463
libc-960626               15463
libc-960627               15463
libc-960628               15463
libc-960629               15554
libc-960630               15554
libc-960701               15554
libc-960702               15554
libc-960703               15554
libc-960704               15554
libc-960705               15554
libc-960706               15554
libc-960707               15554
libc-960708               15620
libc-960709               15620
libc-960710               15620
libc-960711               15620
libc-960712               15620
libc-960713               15620
libc-960714               15620
libc-960715               15673
libc-960716               15702
libc-960717               15702
libc-960718               15702
libc-960719               15702
libc-960720               15702
libc-960721               15702
libc-960722               15702
libc-960723               15702
libc-960724               15702
libc-960725               15702
libc-960726               15702
libc-960727               15702
libc-960728               15702
libc-960729               15702
libc-960730               15702
libc-960731               15702
libc-960801               15702
libc-960802               15702
libc-960803               15702
libc-960804               15702
libc-960805               15702
libc-960806               15702
libc-960807               15702
libc-960808               15702
libc-960809               15702
libc-960810               15702
libc-960811               15702
libc-960812               15702
libc-960813               15702
libc-960814               15702
libc-960815               15702
libc-960816               15702
libc-960817               15702
libc-960818               15702
libc-960819               15702
libc-960820               15702
libc-960821               15702
libc-960822               15702
libc-960823               15702
libc-960824               15702
libc-960825               15702
libc-960826               15702
libc-960827               15702
libc-960828               15702
libc-960829               15702
libc-960830               15702
libc-960831               15702
libc-960901               15702
libc-960902               15702
libc-960903               15702
libc-960904               15702
libc-960905               15702
libc-960906               15702
libc-960907               15702
libc-960908               15702
libc-960909               15702
libc-960910               15702
libc-960911               15702
libc-960912               15702
libc-960913               16178
libc-960918               16190
libc-960919               16190
libc-960920               16190
libc-960921               16190
libc-960922               16190
libc-960923               16190
libc-960925               16307
libc-960926               16307
libc-960927               16307
libc-960928               16307
libc-960929               16307
libc-961001               16307
libc-961004               16307
libc-961005               16307
libc-961006               16307
libc-961007               16307
libc-961008               16307
libc-961009               16307
libc-961010               16307
libc-961011               16307
libc-961012               16307
libc-961013               16307
libc-961014               16307
libc-961015               16307
libc-961016               16307
libc-961017               16307
libc-961018               16307
libc-961019               16307
libc-961020               16307
libc-961021               16307
libc-961022               16307
libc-961023               16307
libc-961024               16307
libc-961025               16307
libc-961026               16307
libc-961027               16307
libc-961028               16307
libc-961029               16482
libc-961030               16482
libc-961031               16482
libc-961101               16482
libc-961102               16482
libc-961103               16482
libc-961104               16482
libc-961105               16482
libc-961106               16482
libc-961107               16482
libc-961108               16540
libc-961109               16540
libc-961110               16540
libc-961111               16540
libc-961114               16576
libc-961115               16576
libc-961116               16576
libc-961117               16576
libc-961118               16576
libc-961119               16576
libc-961120               16601
libc-961121               16602
libc-961203               16607
libc-961204               16607
libc-961205               16607
libc-961206               16607
libc-961207               16607
libc-961208               16638
libc-961209               16638
libc-961210               16638
libc-961211               16664
libc-961212               16664
libc-961213               16664
libc-961214               16664
libc-961215               16664
libc-961216               16664
libc-961217               16664
libc-961218               16664
libc-961219               16664
libc-961220               16664
libc-961221               16664
libc-961222               16664
libc-961223               16664
libc-961224               16664
libc-961225               16664
libc-961226               16664
libc-961227               16664
libc-961228               16664
libc-961229               16664
libc-961230               16664
libc-961231               16664
libc-970101               16802
libc-970102               16802
libc-970103               16802
libc-970104               16821
libc-970105               16833
libc-970106               16833
libc-970107               16833
libc-970108               16843
libc-970109               16843
libc-970110               16843
libc-970111               16843
libc-970112               16843
libc-970113               16843
libc-970114               16843
libc-970115               16843
libc-970116               16843
libc-970117               16843
libc-970118               16843
libc-970119               16843
libc-970120               16843
libc-970121               16843
libc-970122               16843
libc-970123               16843
libc-970124               16843
libc-970125               16843
libc-970126               16843
libc-970127               16843
libc-970128               16843
libc-970129               16843
libc-970130               16843
libc-970131               16843
libc-970201               16843
libc-970202               16843
libc-970203               16843
libc-970204               16843
libc-970205               16843
libc-970206               16843
libc-970207               16843
libc-970208               16843
libc-970209               16843
libc-970210               16843
libc-970211               16843
libc-970212               16843
libc-970213               16843
libc-970214               16843
libc-970215               16843
libc-970216               16843
libc-970217               16843
libc-970218               16843
libc-970219               16843
libc-970220               16843
libc-970221               16843
libc-970222               16843
libc-970223               16843
libc-970224               16843
libc-970225               16843
libc-970226               16843
libc-970227               16843
libc-970228               16843
libc-970301               16843
libc-970302               16843
libc-970303               16843
libc-970304               16843
libc-970305               16843
libc-970306               16843
libc-970307               16843
libc-970308               16843
libc-970309               16843
libc-970310               16843
libc-970311               16843
libc-970312               16843
libc-970313               16843
libc-970314               16843
libc-970315               16843
libc-970316               16843
libc-970317               16843
libc-970318               16843
libc-970319               16843
libc-970320               16843
libc-970321               16843
libc-970322               16843
libc-970323               16843
libc-970324               16843
libc-970325               17242
libc-970326               17242
libc-970327               17242
libc-970328               17242
libc-970329               17242
libc-970330               17242
libc-970331               17242
libc-970401               17242
libc-970402               17242
libc-970403               17242
libc-970404               17242
libc-970405               17242
libc-970406               17242
libc-970407               17242
libc-970408               17242
libc-970409               17242
libc-970410               17242
libc-970411               17242
libc-970412               17404
libc-970413               17404
libc-970414               17404
libc-970415               17404
libc-970416               17404
libc-970417               17404
libc-970418               17500
libc-970419               17500
libc-970420               17500
libc-970421               17500
libc-970422               17500
libc-970423               17500
libc-970424               17500
libc-970425               17500
libc-970426               17500
libc-970427               17500
libc-970428               17500
libc-970429               17500
libc-970430               17500
libc-970501               17500
libc-970502               17500
libc-970503               17500
libc-970504               17500
libc-970505               17500
libc-970506               17675
libc-970507               17675
libc-970508               17693
libc-970509               17693
libc-970510               17693
libc-970511               17693
libc-970512               17693
libc-970513               17693
libc-970514               17693
libc-970515               17693
libc-970516               17693
libc-970517               17693
libc-970518               17693
libc-970519               17693
libc-970520               17693
libc-970521               17693
libc-970522               17693
libc-970523               17693
libc-970524               17693
libc-970525               17693
libc-970526               17693
libc-970527               17693
libc-970528               17693
libc-970529               17693
libc-970530               17693
libc-970531               17693
libc-970601               17693
libc-970602               17693
libc-970603               17693
libc-970604               17693
libc-970605               17693
libc-970606               18148
libc-970607               18148
libc-970608               18164
libc-970609               18174
libc-970610               18209
libc-970611               18209
libc-970612               18209
libc-970613               18209
libc-970614               18209
libc-970615               18209
libc-970616               18209
libc-970617               18209
libc-970618               18209
libc-970619               18209
libc-970620               18209
libc-970621               18209
libc-970622               18209
libc-970624               18421
libc-970625               18421
libc-970626               18421
libc-970627               18421
libc-970628               18473
libc-970629               18473
libc-970630               18473
libc-970701               18473
libc-970702               18473
libc-970703               18473
libc-970704               18473
libc-970705               18473
libc-970707               18663
libc-970708               18663
libc-970709               18663
libc-970710               18663
libc-970713               18663
libc-970715               18780
libc-970717               18824
libc-970718               18824
libc-970719               18824
libc-970720               18824
libc-970721               18889
libc-970722               18889
libc-970723               18889
libc-970724               18889
libc-970725               18889
libc-970726               18889
libc-970727               19000
libc-970728               19000
libc-970729               19030
libc-970730               19030
libc-970731               19030
libc-970801               19030
libc-970802               19074
libc-970803               19074
libc-970804               19074
libc-970805               19074
libc-970806               19074
libc-970807               19074
libc-970808               19074
libc-970809               19074
libc-970810               19074
libc-970811               19074
libc-970812               19074
libc-970813               19074
libc-970814               19074
libc-970815               19074
libc-970816               19074
libc-970817               19074
libc-970818               19074
libc-970819               19074
libc-970820               19074
libc-970821               19074
libc-970822               19074
libc-970823               19472
libc-970824               19472
libc-970825               19472
libc-970826               19472
libc-970827               19541
libc-970828               19541
libc-970829               19541
libc-970830               19541
libc-970831               19541
libc-970901               19541
libc-970902               19541
libc-970903               19541
libc-970904               19541
libc-970905               19541
libc-970906               19766
libc-970907               19766
libc-970908               19766
libc-970911               19861
libc-970912               19861
libc-970913               19861
libc-970914               19861
libc-970915               19861
libc-970916               19861
libc-970917               19861
libc-970918               19861
libc-970919               19861
libc-970920               19861
libc-970921               19861
libc-970922               19861
libc-970923               19861
libc-970924               19861
libc-970925               19861
libc-970926               19861
libc-970927               19861
libc-970928               19861
libc-970929               19861
libc-970930               19861
libc-971001               19861
libc-971018               19861
libc-971019               19861
libc-971020               19861
libc-971021               19861
libc-971022               19861
libc-971023               19861
libc-971024               19861
libc-971025               19861
libc-971026               19861
libc-971027               19861
libc-971028               19861
libc-971029               19861
libc-971030               19861
libc-971031               19861
libc-971101               19861
libc-971102               19861
libc-971103               19861
libc-971104               19861
libc-971105               19861
libc-971106               19861
libc-971107               19861
libc-971108               19861
libc-971109               19861
libc-971110               19861
libc-971111               19861
libc-971112               19861
libc-971113               19861
libc-971114               19861
libc-971115               19861
libc-971116               19861
libc-971117               19861
libc-971118               19861
libc-971120               19861
libc-971121               19861
libc-971122               19861
libc-971123               19861
libc-971124               19861
libc-971125               19861
libc-971126               19861
libc-971127               19861
libc-971128               19861
libc-971129               19861
libc-971130               19861
libc-971201               19861
libc-971203               19861
libc-971204               19861
libc-971205               19861
libc-971206               19861
libc-971207               19861
libc-971208               19861
libc-971209               19861
libc-971210               19861
libc-971211               19861
libc-971212               19861
libc-971213               19861
libc-971214               19861
libc-971217               19861
libc-971218               19861
libc-971219               19861
libc-971220               19861
libc-971221               19861
libc-971222               19861
libc-971223               19861
libc-971224               19861
libc-971225               19861
libc-971226               19861
libc-971227               19861
libc-971228               19861
libc-971229               19861
libc-971230               19861
libc-971231               19861
libc-980103               19861
libc-980104               19861
libc-980105               19861
libc-980106               19861
libc-980107               19861
libc-980108               19861
libc-980109               19861
libc-980110               19861
libc-980111               19861
libc-980112               19861
libc-980114               19861
libc-980115               19861
libc-980116               19861
libc-980117               19861
libc-980118               19861
libc-980119               19861
libc-980120               19861
libc-980121               19861
libc-980122               19861
libc-980123               19861
libc-980124               19861
libc-980125               19861
libc-980126               19861
libc-980127               19861
libc-980128               19861
libc-980129               20797
libc-980130               20797
libc-980212               20832
libc-980213               20832
libc-980214               20893
libc-980215               20893
libc-980216               20893
libc-980217               20893
libc-980218               20893
libc-980219               20893
libc-980220               20893
libc-980221               20893
libc-980222               20893
libc-980223               20893
libc-980224               20893
libc-980225               20893
libc-980226               20893
libc-980227               20893
libc-980228               20893
libc-980301               20893
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libc-980306               20893
libc-980307               20893
libc-980308               20893
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libc-980310               20893
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libc-980312               20893
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libc-980314               20893
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libc-980316               20893
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libc-980320               20893
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libc-980322               20893
libc-980323               20893
libc-980324               20893
libc-980325               20893
libc-980326               20893
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libc-980331               20893
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libc-980621               22478
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libc-980625               22478
libc-980626               22478
libc-980627               22478
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libc-980702               22478
libc-980703               22478
libc-980704               22478
libc-980705               22478
libc-980706               22478
libc-980707               22478
libc-980708               22478
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libc-980715               22478
libc-980716               22478
libc-980717               22478
libc-980718               22478
libc-980719               22478
libc-980720               22787
libc_1_09                 10803
make-3-72-9               10364
make-3-72-10              10364
make-3-72-11              10364
make-3-72-12              10364
make-3-72-13              10364
make-3-73                 10364
make-3-73-1               10364
make-3-73-2               10364
make-3-73-3               11789
make-3-74                 11789
make-3-74-1               12800
make-3-74-2               12800
make-3-74-3               14458
make-3-74-4               14846
make-3-74-5               15594
make-3-74-6               15594
make-3-74-7               15594
make-3-75                 15594
make-3-75-1               18912
make-3-75-91              18912
make-3-75-92              19342
make-3-75-93              21502
make-3-76                 19768
make-3-76-1               19768
release-0-0               15702
release-0-1               15702
release-1-0               17404
Release_5_25              24283
root-libc-2_0_x-branch    16843
